1. Field of the Invention
This invention relates to polygraph machines and more specifically to the enhancement of the polygraph data evaluation by the incorporation of a spectral analyses thereby eliminating inconclusive results and producing supplemental and recognizable polygraph data for more accurate examinations.
2. Discussion of the Prior Art
A conventional polygraph machine or lie detector as described in the Article "The Polygraph", by Burke M. Smith, Scientific American, January 1967, Vol. 216, No. 1, pg 25 in use today helps to determine whether or not a person is telling the truth. The apparatus is designed to detect and record changes that occur in the human body as an individual responds to certain questions. Such changes are known to occur in the respiratory system, pulse, blood pressure, nervous system, and sweat gland response.
Although many experts believe that such tests are extremely accurate measures of a person's integrity and veracity, the polygraph apparatus and the results are continuously being challenged and may fail to provide conclusive results.
In the current polygraph data reduction process, the data is only monitored from a time history standpoint using an uncalibrated amplitude scale as an integrity indicator with relative amplitudes compared to known true and false statement. True response generate little pen motion and false statements cause large pen motions, or pegging. In scaling to minimize the pegging, "deceptive" or "somewhat false" responses may cause the pens to oscillate only slightly. This may be a result of the frequency response of the polygraph machine being too low (machines of this type typically cannot record above 60 Hz), or indicative of possibly another response frequency present other than a fundamental. It, of course must be realized that most system response has some oscillation to it but the frequency content can greatly vary.
It is well known that viewing data in only time history terms may be insufficient in providing conclusive structural integrity evidence. When problems occur other frequencies are typically produced which can be interpreted as signs of deterioration and a means of early detection provided. This appears to be the case in monitoring a human being's integrity. For example, the feeling one has that from the way a person makes a statement an impression he is lying in his tone of voice is given. The monitors used on a polygraph test may detect a tenseness, or modulation, in the involuntary nervous system which causes not only a tone change to be heard, but also may be detectable in the normally monitored polygraph data.